In a general wet washing process, a process of washing the surface of a washing object using a washing solution is performed to remove foreign substances or pollutants attached on the surface of the washing object. In this process, it is general that the washing solution is injected at a high speed or churned using ultrasonic waves or the like to enhance efficiency of washing.
Meanwhile, after the washing process is finished, some of the washing solution and the foreign substances or pollutants always remain on the surface of the washing object.
It is apparent that some of the foreign substances or pollutants remain in the washing solution after the washing is finished as described above, and, in addition, molecules or ions of an additive added to the washing solution to improve cleaning power remain together with the washing solution. Therefore, it is general to perform an additional drying process to remove the washing solution remaining as described above.
Although liquid materials (solvents) forming the washing solution is quickly removed in the drying process through evaporation, a large amount of melt or floating materials is not removed and still remains on the surface, and thus a separate removing process is additionally required.
In addition, there is a problem in that a secondary defect occurs due to the remaining materials.